CANNES – Completing a loose trilogy on the Pinochet dictatorship that he began with Tony Manero and Post Mortem, Chilean director Pablo Larrain delves deep into the behind-the-scenes machinations of political marketing in No, a dense chronicle of the 1988 plebiscite that led to Chile’s first democratically elected government in 17 years. Anchored by an admirably measured performance from Gael Garcia Bernal as the maverick advertising ace who spearheaded the winning campaign, the quietly impassioned film – financed by Participant Media – seems a natural for intelligent arthouse audiences. But it faces a considerable central challenge.

That obstacle is the decision by Larrain, working with cinematographer Sergio Armstrong, to shoot the entire film using a period-appropriate U-matic video camera from the early ‘80s. The choice makes aesthetic sense in terms of evoking the era and allowing for dramatic scenes to be smoothly integrated with extensive archival footage, including large chunks from referendum TV spots for both Yes and No sides. But it’s commercially damaging. Theatrical distributors will likely be hesitant to present a film that by today’s hi-def standards looks murky and flat. That said, audience response to the first Directors Fortnight screening in Cannes was ecstatic, indicating a robust festival life at the very least.

Adapted by Pedro Peirano (The Maid) from Antonio Skarmeta’s play Referendum, the story centers on René Saavedra (Bernal), a composite of the two men most instrumental in the anti-regime No campaign. (They make cameo appearances here, ironically as Pinochet flunkies.)

Like a latter-day Don Draper, René is amusingly introduced presenting a cheesy American-style commercial for Free cola to clients, its zesty message selling a spirit of youthful rebellion meant to represent the new Chile. Approached to work on the No campaign by Urrutia (Luis Gnecco), a veteran Socialist with connections to his family, René is initially ambivalent. The referendum is viewed as a charade with a foregone conclusion – a concession to mounting international pressure to legitimize the Pinochet government. René’s estranged wife Veronica (Antonia Zegers), a leftist radical, is especially dismissive of the exercise. But driven in part by the legacy of his political-dissident father, René gets on board with Urrutia’s conviction that the No vote could actually pass.

His involvement is complicated by the fact that his oily ad agency boss, Lucho Guzman (Alfredo Castro), is firmly in the Pinochet camp. He reports to a smug minister (Jaime Vadell) and steps up his consultancy when the Yes think tank gets nervous that public support is shifting to a No vote.

Following a model not unlike that of Dustin Lance Black’s screenplay for Milk, Peraino has René assemble a group of trusted collaborators. That includes his former mentor (Nestor Cantillana), who nervously insists on remaining behind the scenes for fear of repercussions, and a prickly cameraman-director (Marcial Tagle). But the opportunities for character development and inter-personal conflict are under-explored, instead favoring painstakingly detailed accounts of the rival campaigns. More attention could also have been given to a mildly suspenseful thread running through, as regime scare tactics unsettle the No team, causing René to fear for the safety of his young son (Pascal Montero).

But while the film’s human drama – including René’s melancholy attempts to reunite his family – is a little low on emotional impact, the nitty-gritty of the campaign’s evolution provides an engrossing narrative.

Raising the hackles of hardliners who feel the scant 15-minute nightly allocation of national airtime should go to evidence of violence, exiles, desaparecidos and other human rights violations under Pinochet, René instead turns to the same strategies used to sell sodas and microwaves. He reasons that middle-class complacency and fear of a return to poverty will limit voter turnout, so remolds the spots to focus on the promise of happiness. A rainbow logo is slapped on the campaign, with footage of sunny meadows and exultant dancers backed by an upbeat anthem. A tad more economy here might have helped pump tension in the run-up to the vote, but given the fascination with advertising driven by Mad Men, there are worse areas in which to dawdle.

A welcome strain of sly humor accompanies the use of hokey marketing tricks and simplistic messages to bring down a dictatorship. That element is enhanced when the Yes side, aided by Guzman, modifies its campaign accordingly. The film also ends on a note of droll cynicism. Via Bernal’s subdued intensity and the look of skepticism with which he acknowledges his victory, Larrain hints that René’s methods are part of a somewhat Faustian pact, and that newly democratic Chile would continue to be a country divided along lines of wealth and power.

Venue: Cannes Film Festival (Directors Fortnight)

Production companies: Participant Media, in association with Funny Balloons, Fabula